1. Field of the Invention
This invention relates generally to an individual contact for a multicircuit electrical connector; and more particularly to such a contact that has an associated electrical component for bypassing undesired frequencies or overvoltages to ground.
2. Prior Art
The first association of electrical components with individual contacts inside a multicircuit connector was achieved by placing the components axially in line with the contacts. Pulse absorbers and radio-frequency filters were among the components so installed.
Subsequently U.S. Pat. No. 3,790,858 to Brancaleone and Oliver showed that electrical components could instead be placed adjacent to the contacts. The components were electrically connected between the respective individual contacts and a common grounding plate spanning the interior of the shell; a parallel insulating plate with printed-circuit connections served to complete the individual contact-to-component connections.
That configuration permitted shorter connectors, while maintaining reasonable connector diameter and minimizing lead inductances. Completing the multiple interconnections to the parallel plate, however, was essentially a one-time factory operation; the Brancaleone connector once assembled was not readily serviced--particularly in the field.
Such a connector configuration has two major limitations. First, the failure rate of such a connector is in effect the aggregate of the failure rates for all the individual electrical components. Even at the factory, replacement of an individual component is at best awkward and relatively expensive.
Second, electrical damage to an individual electrical component when in use creates very nearly the same service gridlock seen commonly with other preassembled printed-circuit boards: the entire board--or here the entire connector--must be returned for repair. Attempts to correct such problems in the field require extraordinary manual dexterity and specialized experience.
Even if these resources are available, such attempts usually are severely uneconomic. As a consequence, entire equipments may be taken out of service for failure of a single commonplace element worth just pennies.
More modern efforts are typified by U.S. Pat. Nos. 4,600,262 to Nieman et al., 4,582,385 to Couper et al., and 4,572,600 also to Nieman. These inventors sought to make the individual contacts individually replaceable with ease, in the field as well as at the factory.
These three patents teach mounting of diode chips in lateral notches cut into the sides of the individual contacts. Each diode chip thus rides on its respective contact, and can be inserted into the connector and withdrawn from it on a modular basis.
One side of each chip is electrically connected with its contact at the mounting point. In all three of these just-mentioned patents, the other side of each diode chip is grounded to a spring-loaded grounding element during insertion of the contact axially into the grounding plate.
More specifically, in the first two of these three patents, the second side of each chip is left exposed in its notch and engages a spring-loaded grounding tang in the ground plate directly. In the third patent, the second side of each chip is instead permanently connected to a metallic grounding strip that extends axially along the outside of the contact to a circumferential grounding band, which in turn engages a pair of grounding springs in the grounding plate.
Unfortunately these notch-mounted-chip configurations have proven troublesome. In all three forms, the diode chips are subject to failure from mechanical shock during assembly of the contacts into the connector--and also from mechanical and thermal shock later, from humidity and chemical fumes in the operating environment, and probably from other unknown causes.
The resulting connector assemblies are thus much too sensitive for reliable, practical use. Moreover, the connector contacts often are at critical points in the associated circuitry, so that these failures cause serious problems in operation of the overall apparatus to which the connector attaches.